Absorbent article having a color-pigmented and printed backsheet

ABSTRACT

The present invention relates to disposable absorbent articles such as diapers and adult incontinence products, which collect and retain urine and fecal material deposited thereon by the wearer. The disposable absorbent articles of the present invention comprise a color-pigmented backsheet, which further comprises visually discernible ornamental designs printed thereon.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.60/435,625, filed Dec. 20, 2002.

FIELD OF THE INVENTION

The present invention relates to disposable absorbent articles such asdiapers and adult incontinence products, which collect and retain urineand fecal material deposited thereon by the wearer. The disposableabsorbent articles of the present invention comprise a color-pigmentedbacksheet, which further comprises visually discernible ornamentaldesigns printed thereon.

BACKGROUND OF THE INVENTION

In short-period usage absorbent articles such as daytime diapers, light,thin and flexible materials are especially desirable to provide improvedfreedom of movement and increased comfort for the wearer. Therefore, itis preferred to apply materials like polymeric films or nonwoven webswith very low basis weights.

However, a drawback of a disposable article using very low basis weightmaterials is that these materials have an increased tendency to betranslucent. It is difficult to manufacture thin materials, whichprovide a desired degree of opacity, because only a limited amount ofwhiteners, such as titanium dioxide, can be added without receivingmaterials, which are brittle and tend to disintegrate easily.

The problem of translucency in light, thin, and flexible absorbentarticles is further increased by the fact, that such articles maycomprise regions with only very few overlying layers of material. Forexample, in a diaper the use of a thin and relatively small absorbentcore results in a relatively large area in the front and/or rear waistregion of the diaper, which only comprises a topsheet and a backsheetoverlying each other.

While light, thin and flexible diapers with improved freedom to move arehighly appreciated by the consumer, translucency is usually disliked bythe wearer or caretaker. The skin of the wearer is shining through thediaper in some areas and moreover, the structural features inside thediaper, like for example elastics or parts of the absorbent core, can beseen from the outside due to thin covering materials. Hence, the diapertends to get a rather patchy appearance.

The above-said becomes even more problematic, when the diaper is soiledand the stains of the absorbed exudates shine through, due to a thinabsorbent core and a light, translucent backsheet.

It is thus an objective of the present invention to provide a light,thin and flexible absorbent article with an improved outer appearancewithout the need to employ economically unattractive materials.

It is a further objective of the present invention to provide a light,thin absorbent article, which looks like an undergarment, especially foruse as a daytime diaper.

Color-printed materials for use in absorbent articles are well known inthe art:

-   -   WO 99/60973 filed May 28, 1998 entitled “Clothlike, breathable        backsheet with multicolored graphics for disposable absorbent        article” discloses absorbent articles with a backsheet        comprising a microporous polymer film printed with multicolored        graphics and a nonwoven material laminated to the film. The        microporous film has a “b” value from 0.0 to 0.5 and less than        4% thermal shrinkage at 50° C. and 50% relative humidity for one        week.    -   WO 99/32164 filed Dec. 19, 1997 entitled “Disposable absorbent        articles comprising microporous polymer films with registered        graphics” relates to absorbent articles with a backsheet        comprising a microporous film printed with a registered graphic        and comprising by weight 30-60% polyolefin and 40 to 80% calcium        carbonate. The microporous film has a “b” value from 0 to 5 and        less than 2% thermal shrinkage at 50° C. and 50% relative        humidity for one week.

One drawback with printing is, that printing large areas of thebacksheet becomes expensive and thus, is not economically attractive.Moreover, to receive intense colors, high amounts of ink have to beapplied, which—besides raising expenses—may lead to the rubbing-off ofink during use of the disposable article.

Besides printing, other techniques to improve the appearance ofmaterials for use in absorbent articles have been developed:

-   -   WO 93/19714 filed Mar. 22, 1993 entitled “Multilayer film        exhibiting an opaque appearance” discloses a mulitlayer film        comprising two outer layers and a central polymeric layer. The        central layer has high concentrations of pigments or other        fillers to increase the masking ability. The central layer may        be whitened or colored. However, due to the number of layers,        the multiplayer film is rather thick and thus not very suitable        for use in a light, flexible diaper.    -   WO 96/10380 filed Aug. 4, 1995 entitled “Laminate material and        absorbent garment comprising same” refers to a laminate material        with a first layer having opaque areas, transparent areas and a        coloration and a second layer having a different coloration than        the first layer. The coloration of the second layer is visible        through the transparent areas of the first layer to a greater        extent than through the opaque areas of the first layer.    -   EP 1 252 873 A2 and EP 1 247 508 A2 both filed Apr. 04, 2002 and        both entitled “Discreet absorbent articles” disclose absorbent        articles comprising a pigmented cover, a pigmented apertured        transfer layer and a pigmented backsheet, which provides masking        of synthetic menstrual fluid and discretion.    -   WO 00/38915 filed Dec. 29, 1999 entitled “Pattern embossed        multiplayer microporous Films” discloses a multilayer film with        first microporous layer having at least 35% filler and second        microporous layer having at least 35% filler and a coloring        agent. The first and second layer are continuously joined        together and have embossed and non-embossed regions wherein the        embossed regions color-contrast with the non-embossed regions.

However, all those techniques are rather complex and thus expense.Furthermore, they tend to require materials with high basis weight dueto the need for several layers, which generally is disliked in a light,highly flexible absorbent article.

Thus, it is a further objective of the present invention to providemulticolored absorbent articles, which are thin, light and highlyflexible due to use of thin materials with low basis weight.

These articles should at the same time provide an attractive outerappearance, provide improved freedom of movement and increased comfortfor the wearer and allow the use of economical attractive materials.

SUMMARY OF THE INVENTION

The present invention provides disposable articles selected from babydiapers, pull-on diapers, pants or adult incontinence diapers comprisinga liquid pervious topsheet, a liquid impervious backsheet and anabsorbent core positioned between the topsheet and the backsheet,wherein the backsheet comprises at least one polymeric film and at leastone nonwoven web, the polymeric film and the nonwoven web each have twomajor surfaces and the polymeric film and the nonwoven web both comprisea polymeric material, at least one of the polymeric materials of thefilm or of the nonwoven web is colored by pigments comprised within thepolymeric material and wherein at least one of the polymeric film or thenonwoven web has visually discernible ornamental designs, the designsbeing provided by printing a pigmented ink onto at least one of themajor surfaces of at least one of the polymeric film or the nonwoven weband the polymeric film being joined in an overlaying region across atleast part of one of its major surfaces to at least part of an adjacentmajor surface of the nonwoven web to form the backsheet and wherein thebacksheet in the overlaying region has a L Hunter value on the Hunterscale for darkness/lightness-appearance from about 10 to about 75, an“a” value for red/green-appearance from about −50.0 to about +50.0 andan “b” value for yellow/blue-appearance from about −50.0 to about +50.0in the areas outside the printed ornamental designs.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the following terms have the following meaning:

-   -   “Absorbent article” refers to devices that absorb and contain        liquid, and more specifically, refers to devices that are placed        against or in proximity to the body of the wearer to absorb and        contain the various exudates discharged from the body. Absorbent        articles of the present invention include baby diapers, pull-on        diapers, pants or adult incontinence diapers.    -   “Disposable” is used herein to describe articles that are        generally not intended to be laundered or otherwise restored or        reused i.e., they are intended to be discarded after a single        use and, preferably, to be recycled, composted or otherwise        disposed of in an environmentally compatible manner.    -   “Baby diapers”, “pull-on diapers”, “pants” and “adult        incontinence diapers” refer to absorbent articles generally worn        by infants or incontinent persons about the lower torso.    -   “Attached” or “Joined” encompasses configurations whereby an        element is directly secured to another element by affixing the        element directly to the other element, and configurations        whereby an element is indirectly secured to another element by        affixing the element to intermediate member(s) which in turn are        affixed to the other element.    -   “Comprise,” “comprising,” and “comprises” is an open ended term        that specifies the presence of what follows e.g. a component but        does not preclude the presents of other features, elements,        steps or components known in the art, or disclosed herein.

The disposable absorbent articles of the present invention generallycomprise the same features as the baby diapers, pull-on diapers, pantsor adult incontinence diapers known in the art. The absorbent articlecomprises a chassis, which makes up the main body of the absorbentarticle. The chassis comprises an outer covering including a liquidpervious topsheet and a liquid impervious backsheet. The chassis mayalso include most or ail of the absorbent core encased between thetopsheet and the backsheet. The chassis preferably further includes legcuffs, waist features and/or side panels. The leg cuffs, side panelsand/or the waist feature may comprise elastic members. The front endportion of the absorbent article is configured as the front waist regionwith the outer edge being the front waist edge. The opposite rear endportion is configured as the rear waist region of the absorbent articlewith the outer edge being the rear waist edge. An intermediate portionof the absorbent article is configured as the crotch region, whichextends longitudinally between the front and rear waist regions. Thecrotch region is that portion of the absorbent article which, when theabsorbent article is worn, is generally positioned between the wearer'slegs. The waist regions may include a fastening system comprisingfastening members preferably attached to the rear waist region and alanding zone attached to the front waist region. The absorbent articlehas a longitudinal axis and a transverse axis. The periphery of theabsorbent article is defined by the outer edges of the absorbent articlein which the longitudinal edges run generally parallel to thelongitudinal axis of the absorbent article and the end edges rangenerally parallel to the transverse axis of the absorbent article.

The topsheet may comprise a wide variety of materials and configurationswell known in the art for disposable absorbent articles.

The absorbent core generally is disposed between the topsheet and thebacksheet. The absorbent core may comprise any absorbent material, whichis generally compressible, conformable, non-irritating to the wearer'sskin, and capable of absorbing and retaining liquids such as urine andother certain body exudates. The absorbent core mav comprise a widevariety of liquid-absorbent materials commonly used in disposableabsorbent articles and other absorbent articles. The absorbent corecomprises a rear and the front core edge, which ran generally parallelto the transverse axis of the absorbent article. In a preferredembodiment of the present invention, the absorbent article is a light,thin absorbent article wherein the distance between the rear core edgeand the rear waist edge is at least 40 mm, more preferably at least 45mm and most preferably at least 50 mm.

The absorbent article may also include other features known in the artincluding front and rear ear panels, waist cap features, elastics andthe like to provide better fit, containment and aestheticcharacteristics.

Absorbent articles according to the present invention may be providedwith re-closable fastening system or may alternatively be provided inthe form of unitary absorbent articles, such as pull-on absorbentarticles or pant-type absorbent articles.

The fastening system is preferably comprised by the waist regions andensures that the absorbent article is kept in place about the wearer.The fastening system may comprise fastening members, which arepreferably attached to the rear waist region. In a preferred embodimentthe fastening system further comprises a landing zone attached to thefront waist region. The fastening member is attached to the front waistregion, preferably to the landing zone to form leg openings and a waistopening.

The backsheet is generally the portion of the absorbent articlepositioned with the absorbent core between the backsheet and thetopsheet. The backsheet may be joined with the topsheet. The backsheetprevents the exudates absorbed by the absorbent core and containedwithin the article from soiling other external articles that may contactthe absorbent article, such as bed sheets and undergarments. Thebacksheet is impervious to liquids (e.g., urine) and comprises alaminate of at least one nonwoven and at least one polymeric film suchas a thermoplastic film. The polymeric film preferably has a thicknessfrom about 0.008 mm to about 0.060 mm, more preferably from about 0.010mm to about 0.040 mm and even more preferably from about 0.010 mm toabout 0.020 mm. The polymeric film may be breathable or non-breathable,thus the backsheet may be breathable or non-breathable.

Preferably the backsheet has a basis weight from about 17 gsm to about125 gsm (grams per square meter), more preferably from about 20 gsm toabout 70 gsm and even more preferably from about 20 gsm to about 40 gsm,wherein the polymeric film, has a basis weight from about 10 gsm toabout 60 gsm, more preferably from about 10 gsm to about 30 gsm and evenmore preferably from about 10 gsm to about 20 gsm, and the nonwoven webhas a basis weight from about 7 gsm to about 65 gsm, more preferablyfrom about 10 gsm to about 40 gsm and even more preferably from about 10gsm to about 20 gsm.

The polymeric film of the present invention may be produced fromdifferent types of thermoplastic polymers, preferably polyolefins andthe copolymers of poly olefins. The polymeric film may be formed bycoextrusion processes well known in the art. An inorganic filler (e.g.titanium dioxide) and the thermoplastic polymer are blended together toform a homogeneous mixture in a suitable mixing extruder, or in aseparate preliminary compounding step.

Suitable polyolefins include polyethylenes (PE), such as linear lowdensity polyethylene (LLDPE), low density polyethylene (LDPE), ultra lowdensity polyethylene (ULDPE), high density polyethylene (HDPE), orpolypropylene (PP) and blends thereof. The mixture is then cast or blowninto a film. In embodiments, where the polymeric film comprisesdifferent polyolefins, the different polyolefins may be comprised withinthe polymeric film in different layers or may be coextruded to form asingle blended layer. In a preferred embodiment of the presentinvention, the polymeric film is a coextruded multilayer film comprisingPE, PP and copolymers.

Nonwoven webs can be formed by many processes well known in the art suchas meltblowing, spanbonding, carded. The fibers of the nonwoven web maybe staple or continuous filaments or be formed in situ.

The nonwoven webs according to the present invention may comprise fibersmade by nature (natural fibers), made by man (synthetic or man-made), orcombinations thereof. Example synthetic fibers, which are derived fromnatural fibers, include but are not limited to rayon and lyocell, bothof which are derived from cellulose, a natural polysaccharide fiber.Synthetic fibers, which are not derived from natural fibers, can bederived from other natural sources or from mineral sources. Examplesynthetic fibers not derived from natural sources include but are notlimited to polysaccharides such as starch. Example fibers from mineralsources include but are not limited to polyolefin fibers such aspolypropylene, polyethylene fibers and polyester, which are derived frompetroleum, and silicate fibers such as glass and asbestos. However, thenonwoven web of the present invention has to comprise at least somefibers, which are thermoplastic.

The nonwoven web may comprise several layers, wherein each layer maycomprise the same polymers or may comprise different polymers indifferent layers. For example, the nonwoven web may comprise a spimbondlayer (made by a spunbond process), a meltblown layer (made by ameltblown process) and a further spunbond layer(spunbond-meltblown-spunbond, so called SMS nonwoven web). Otherexamples are SSS-(three spunbond layers) or SM-(one spunbond layer andone meltblown layer) nonwoven webs.

The polymeric film is preferably joined to the nonwoven web bylamination processes well known in the art, for example by adhesivelamination, thermo-bonding or extrusion-lamination.

The polymeric film and the nonwoven web both have two major surfaces:One garment-facing surface and one body-facing surface. In a preferredembodiment of the present invention, the garment-facing surface of thepolymeric film is joined to the body-facing surface of the nonwoven web.Thus, the nonwoven web is comprised by the garment-facing layer of thebacksheet laminate in the absorbent article and is making up theoutermost cover of the absorbent article. The polymeric film iscomprised by the body-facing layer of the backsheet laminate in theabsorbent article.

In one embodiment of the present invention the nonwoven web comprised bythe backsheet laminate covers all or substantially all of the garmentfacing surface of the polymeric film to provide the absorbent articlewith a cloth-like look and feel. In an alternative embodiment thenonwoven web may cover only discrete predetermined portions.

In one embodiment of the present invention, the backsheet comprises acoior-pigmented, polymeric film with visually discernible ornamentaldesigns printed on at least one of the two major surfaces of thepolymeric film, the nonwoven web or both.

In an alternative embodiment of the present invention, the backsheetcomprises a color-pigmented nonwoven web with visually discernibleornamental designs printed on at least one of the two major surfaces ofthe polymeric film, the nonwoven web or both.

In still another embodiment of the present invention, the backsheetcomprises a coior-pigmented. polymeric film and a coior-pigmentednonwoven web with visually discernible ornamental designs printed on atleast one of the two major surfaces of the polymeric film, the nonwovenweb or both.

In any of these embodiments, the designs are preferably printed on thegarment-facing surface of the nonwoven web and/or polymeric film.

Furthermore, in any of these embodiments, the polymeric film may bejoined to the nonvvoven web before or after the designs have beenprinted on the polymeric film, on the nonwoven web or on both.

Color-Pigmentation

The coloring agent used to color-pigment the nonwoven web and/or thepolymeric film of the present invention is preferably added beforemelting the thermoplastic material comprised by the nonwoven web and/orpolymeric film. Alternatively, the coloring agent is added after thethermoplastic polymers, which form the polymeric film and/or nonwovenweb, are molten but before the polymeric film is formed by extrusionrespectively before the fibers of the nonwoven web are formed and thenonwoven web is manufactured.

The coloring agents may be generally termed as pigments, referring toinsoluble color matter used in finely dispersed forms. The pigments maybe dyes, organic pigments or inorganic pigments. Exemplary organicpigments may include: C. I. Pigment Yellow 1, C. I. Pigment Yellow 3, C.I. Pigment Yellow 13, C. I. Pigment Red 5, C. I. Pigment Red 7, C. I.Pigment Red 12, C. I. Pigment Red 112, C. I. Pigment Red 122, C. I.Pigment Blue 1, C. I. Pigment Blue 2, C. I. Pigment Blue 16, C. I. VatBlue 4, C. I. Vat Blue 6, or Carbon black. Exemplary inorganic pigmentsmay include: titanium dioxide (e.g., Pigment White 6), carbon black(e.g., Pigment Black 7), iron oxides, ferric oxide black (e.g., PigmentBlack 11), chromium oxide, or ferric ammonium ferrocyanide. Exemplarydyes may include: Solvent Yellow 14, Dispersed Yellow 23, MetanilYellow, Solvent Red 111, Dispersed Violet 1, Solvent Blue 56, SolventOrange 3, Solvent Green 4, Acid Red 52, Basic Red 1, Solvent Orange 63,or Jet Black. The different pigments may be used in any combination andratio. Alternatively, only one pigment may be applied. Based upon weightof the polymeric material, the suitable addition range for the totalamount of coloring agent may be from about 0.1% to about 49%, preferablyfrom about 3% to about 30% more preferably from about 5% to about 20%.

In a preferred embodiment of the present invention, an inorganic ororganic filler (e.g. titanium dioxide) is added together with at leastone second color pigment. Due to the titanium dioxide, the resultingpolymeric film or nonwoven web gets a certain degree of opacity.Alternatively, instead of or additionally to titanium dioxide, calciumcarbonate may be used as “whitener” to ensure opacity. Calcium carbonatealso adds a certain degree of breathability, which may be especiallydesirable in polymeric films. In the case of breathable films, theextruded polymeric film is stretched at least in one direction to impartbreathability to at least a part of the film.

Preferably, the amount of titanium dioxide in the polymeric film is fromabout 0.5% by weight to about 5% by weight, more preferably, the amountis from about 0.5% by weight to about 3% by weight and even morepreferably, the amount is from about 0.5% by weight to about 2.5% byweight. However, in exceptional cases, the amount of titanium dioxide inthe polymeric film may be even up to 10% by weight.

The amount of Calcium carbonate is different in breathable polymericfilms compared to non-breathable polymeric films, because it stronglyadds to breathability. In non-breathable polymeric films the amount ofcalcium carbonate is preferably from about 5% by weight to about 40% byweight, more preferably from about 5% by weight to about 30% by weight.In breathable polymeric films, the amount of calcium carbonate ispreferably from about 40% by weight to about 80% by weight, morepreferably from about 45% by weight to abut 65% by weight.

Preferably, the amount of titanium dioxide or calcium carbonate in thenonwoven web is from about 0.1% by weight to about 2.0% by weight, morepreferably from about 0.1% by weight to about 1.5% by weight. However,the use of titanium dioxide is preferred over the use of calciumcarbonate.

Besides the coloring agents other additives may be applied formanufacturing the polymeric film, e.g. anti-oxidants, UV inhibitors,process aids such as slip agents like silicone.

Printing

According to the present invention, the backsheet is provided withvisually discernible ornamental designs. These designs may either beprinted on the polymeric film, on the nonwoven web or on both. Thedesigns may be in the form of animals, flowers, toys, graphics, likedots or stars, or any other appealing shape. The designs may comprise anumber of different shapes and colors or may, alternatively, compriseonly one design. Moreover, they may be of any size applicable. Only oneor a small number of the designs may be applied on each backsheet.Alternatively, the designs may be applied in multiple copies on eachbacksheet. “Visually Discernible” according to the present inventionmeans that the designs are visible to the naked eye, without the need toapply any auxiliary devices like microscopes or the like (except forcommon spectacles).

The ink composition of the present invention is any liquid composition,which may be printed Onto the nonwoven web or polymeric film.

Components of the ink composition of the present invention may includebut are not limited to: a vehicle such as a solvent or water; a colorantsuch as a pigment; a binder; and other components which may include butare not limited to wax, crosslinking agents, pH control agents,viscosity modifiers, defoamers, dispersants, printing press hygienecontrol agents, preservatives, and corrosion control agents.

As used herein, “ink” refers to any liquid composition or componentsthereof applied to the nonwoven web and/or polymeric film and whichremains thereon in a visible pattern even though components of the inkmay evaporate. The components of the ink composition may be applied tothe nonwoven web and/or polymeric film sequentially or as a mixture. Asused herein, “vehicle” refers to the liquid component of the inkcomposition utilized to convey the ink composition to the surface of thenonwoven web and/or polymeric film. As used herein, “pigment” refers toinsoluble color matter used in finely divided dispersed form to impartcolor to the ink. As used herein, “binder” refers to the adhesivecomponent of the ink composition. The same ink may be used for printingnonwoven webs and for printing polymeric films.

Though the pigments described and used herein for printing theornamental designs are organic pigments, it is understood that the inkcompositions of the present invention could be extended to includeinorganic pigments as well as other organic pigments. Smaller pigmentparticle sizes are preferred over relatively larger size pigmentparticles. The pigment of the present invention preferably has aparticle size of less than 5 microns, more preferably less than 1micron, and even more preferably less than 0.5 microns.

Ink is applied to the nonwoven web and/or polymeric film by printing theink onto the nonwoven web and/or polymeric film.

Printing processes suitable for this invention include but are notlimited to: lithography, letterpress, gravure, screen printing, intaglioand preferably flexography. According to the present invention, afurther suitable printing process is ink jet printing, which is anon-contact printing technique, wherein the ink is applied in smalldroplets. A single color image or multi-color image may be applied tothe nonwoven web and/or polymeric film.

When a single color is applied on a white surface, it is possible tovary the intensity of this color e.g. by varying the add-on level ofcolor per surface area (e.g. by varying the density of ink dots persurface area in a halftone process). It is thus possible to producedifferent shades of one color. It is, however, not possible to producethe effect of an additional second color by varying the add-on level onwhite surfaces.

Contrary, in the present invention it is possible to produce the effectof additional colors due to the color-pigmented surface whereon theornamental designs are printed. For example, when non-transparent,opaque blue ink is printed on a yellow surface without covering thewhole surface (e.g. by allying small, discrete dots in ahalftoning-process), the such treated surface will be visually perceivedas being green. When the same opaque blue ink is applied such, that thewhole surface is completely coved, the surface will be visuallyperceived as being blue. Thus, by covering at least a first area of asurface with opaque ink in a halftoning process while covering at leasta second area completely with the same ink, the effect of an additionalcolor is created. Moreover, by varying the grid pattern of thehalftoning process it is also possible to vary the shades andintensities of these colors.

As used herein, “percent dot coverage” refers to the amount of aspecified print area covered by halftoning dots in relation to the totalspecified print area. In the present invention, the percent dot coverageis preferably between 3% and 90%, more preferably between 10% and 80%.Furthermore, the frequency, size or combination thereof of halftone dotsmay be varied broadly.

Alternatively to applying opaque colors in a halftoning process, it isalso possible to use transparent inks, which are also within the scopeof this invention. When using transparent ink, the thickness of the inkon the surface is varied to produce the effect of a third color. E.g.when transparent blue ink is applied in a thin layer on a yellowsurface, the yellow surface is partially shining through such, thatcolor will be visually perceived as being green. When the transparentblue ink is applied in a relatively thick layer on the yellow surface,almost none of the yellow color will be shining through any more, suchthat the color will be visually perceived as being blue. Thus, bycovering at least a first area of a surface with a relatively thin layerof transparent ink while applying a relatively thick layer of the sameink in at least a second area of the surface, the effect of anadditional color is created.

Moreover, the same effects can be achieved by printing e.g. twodifferent colors in a halftoning process in the same area, such that amixture of dots of at least two different colors is applied. When usingtransparent ink, e.g. two different colors may be printed, overlyingeach other and wherein the add-on level of these inks is varied tocreated the effect of additional colors and different shades. However,when applying this technique on a color pigmented polymeric film ornonwoven web, the “background” color can be used, which enables vivid,multicolored ornamental designs on polymeric films and/or nonwoven webswithout the need for multiple colors. This simplifies the printingprocess, which enables fast and inexpensive printing. In a preferredembodiment of the present invention, two different colors are applied toprint the visible discernible ornamental designs.

When the ornamental designs are printed on the polymeric film or on thenonwoven web comprised by the backsheet, the designs preferably do notcomprise more than 50% of the total surface of at lest one of the twomajor surfaces of the backsheet. More preferably, the ornamental designsdo not comprise more than 40%, still more preferred not more than 30%and most preferred not more than 20% of at lest one of the two majorsurfaces of the backsheet.

In a preferred embodiment of the present invention, more than 60% of theornamental designs printed on the polymeric film and/or the nonwoven webof the backsheet coincide with the area of the backsheet, which iscovered by the absorbent core, more preferably more than 70%, still morepreferably more than 80% and most preferred more than 90%. Thereby, themasking effect of the ornamental designs is improved with respect tostains formed by urine or other exudates disposed in the absorbentarticle.

The ornamental designs may be printed, on either of the two majorsurfaces of the polymeric film and/or the nonwoven web. When theornamental designs are printed on the polymeric film, they arepreferably applied on the garment-facing surface of the film to avoiddirect contact between the ink and the liquids and other exudatesdisposed in the absorbent article. Alternatively, the ornamental designsmay be applied on the body-facing surface of the polymeric film. Whenthe ornamental designs are printed on the nonwoven web, they may beprinted on the body-facing surface or, more preferably, on the garmentfacing surface of the nonwoven web.

To improve the printing capability of the nonwoven web or polymericfilm, the nonwoven web or polymeric film may undergo a corona treatmentprior to printing the ornamental designs.

L Hunter Value and “a” and “b” Values of the Backsheet

The L Hunter value as well as the “a” and “b” values are measured in thearea outside the ornamental designs, thus these values are measured forthe color-pigmented area of the backsheet without comprising the printedarea. Furthermore, the L Hunter value and the “a” and “b” values aremeasured in the area, where the polymeric film is covered by thenonwoven web. Preferably, the L Hunter value and the “a” and “b” valuesare measured on the garment-facing surface of the backsheet and thus onthe surface, where the nonwoven web is facing the viewer. Alternatively,the L Hunter value and the “a” and “b” values are measured on thebody-facing surface of the backsheet and thus on the surface, where thepolymeric film is facing the viewer.

The L Hunter scale values, utilized herein to define thedarkness/lightness of the backsheet according to the present invention,are units of color measurement in the Hunter Color system. A completetechnical description of the system can be found in an article by R. S.Hunter, ‘photoelectric color difference Meter’, Journal of the OpticalSociety of America, Vol. 48, pp.985-95, 1958. Devices specially designedfor the measurement of color on the Hunter scales are described in U.S.Pat. No. 3,003,388 to Hunter et al., issued Oct. 10, 1961. In general,Hunter Color “L” scale values are units of light reflectancemeasurement, and the higher the value is, the lighter the color is sincea lighter colored material reflects more light. In particular, in theHunter Color system the “L” scale contains 100 equal units of division,absolute black is at the bottom of the scale (L=0) and absolute white isat the top of the scale (L=100). Thus in measuring Hunter Color valuesof the materials used in the absorbent articles according to the presentinvention, the lower the “L” scale value, the darker the material.

The backsheet herein might be of any color provided that the L Huntervalue and the “a” value and “b” value defined herein are meet.

‘Color’ as referred to herein include any primary color, i.e. black,white, red, blue, violet, orange, yellow, green, and indigo as well asany declination thereof or mixture thereof.

Colors can be measured according an internationally recognized 3D soliddiagram of colors where all colors that are perceived by the human eyeare converted into a numerical code. This system is based on threedimensions (x,y,z) and specifically L, a, b.

When a color is defined according to this system L represents lightness(0=black, 100=white), a and b independently each represent a two coloraxis, a representing the axis red/green (+a=red, −a=green), while brepresents the axis yellow/blue (+b=yellow, −b=blue).

Any color is identified by a unique AE value, which is mathematicallyexpressed by the equation:

ΔE=[(Lref.−Lsample)2+(aref.−asample)2+(bref.−bsample)2]½

ΔE represents graphically the distance between the reference color andthe no color point (i.e. center of sphere Lref =50, aref=0, bref=0) ofthe 3D model.

Color can be measured using the colorimeter MINOLTA mode CR-300instrument (available from the Minolta Company, Japan) which providesthe coordinates L, a, b and from which the ΔE value can be determined.

According to the present invention the backsheet of the absorbentarticles has a L Hunter value from about 10 to about 75, more preferablyfrom about 10 to about 65, and still more preferably from about 15 toabout 60.

Moreover, the backsheet according to the present invention has an “a”value from about −50.0 to about +50.0, more preferably from about −30.0to about +30.0, even more preferably from about −20.0 to about +20.0 andmost preferred from about −10.0 to about +10.0. Furthermore, thebacksheet according to the present invention has a “b” value from about−50.0 to about +50.0, more preferably from about −35.0 to about +25.0,even more preferably from about −25.0 to about +15.0 and most preferredfrom about −20.0 to about +5.0.

In the present invention the L Hunter values as well as the “a” and “b”values refer to the values for a single layer of the backsheet materialand thus not for several layers of the materials folded upon itself.While carrying out the measurements of the values, the backsheetmaterials are placed directly on a white background.

A backsheet, which is colored such, that it fulfills the above defined LHunter value and the a and b values defined above provides a vivid,shining color. The backsheet further provides improved masking effects,even if the polymeric film and/or the nonwoven web comprised by thebacksheet have reduced opacity. This facilitates the use of smalleramounts of whiteners like titanium dioxide in the polymeric film andtherefore enables reduction of costs while at the same time providingsuperior absorbent articles.

Opacity

The opacity of the backsheet of the present invention is preferably fromabout 55% to about 100%, more preferably from about 55% to about 95% andeven more preferred from about 55% to about 80% and most preferred fromabout 60% to about 70%. According to the present invention opacity ismeasured in the area, where the polymeric film is covered by thenonwoven web. Preferably, the opacity is measured on the garment-facingsurface of the backsheet and thus on the surface, where the nonwoven webis facing the viewer. Alternatively, the opacity is measured on thebody-facing surface of the backsheet and thus on the surface, where thepolymeric film is facing the viewer. Moreover, opacity is measured inthe area outside the ornamental designs, thus for the color-pigmentedarea of the backsheet without comprising the printed area. The opacityis measured by the following test method:

Method to determine the opacity:

-   -   Opacity is measured according to the method described in detail        in WO 01/49230, starting on page 19, and essentially follows the        following description:

Apparatus and Materials

-   -   BYK-Gardner TCS® Color Sphere Spectrophotometer, which is a        spectrophotometer using a d/8° geometry (diffuse illumination        and 8° viewing), with instrument operation manual and software;        available from BYK-Gardner, Inc., Columbia, Md. U.S.A.    -   Menu driven quality control software program; available from        BYK-Gardner, Inc.    -   Small area lens and aperture; available from BYK-Gardner, Inc.    -   Quartz halogen lamp with infrared filter; available from        BYK-Gardner, Inc.    -   Black cavity; available from BYK-Gardner, Inc.    -   White Japanese opal standard, with calibration data; available        from BYK-Gardner, Inc.    -   Cutting device, such as a scissors or paper cutter capable of        cutting specimens to the requisite dimensions as specified        below.

Conditioning: Testing should be conducted in a standard laboratoryatmosphere of 23°+2° C. (73.4°+3.6° F.) and 50%+5% relative humidity.

Test Specimen: For each material to be tested, cut five specimens ofapproximately 51 by 51 millimeters (2 by 2 inches).

Preparation of Apparatus and Materials: For general operation proceduresee operation manual of the Color Sphere Spectrophotometer

The setting configuration should be as follows:

-   -   Color Scale    -   Display: XYZ    -   Illuminant: C    -   Observer: 2°

Calibration: Calibrate with Black cavity and Japanese opal standardtile. Place the tile so that the 2 pegs are resting on top of thereflectance port cover plate.

Compare the nanometer results to the number supplied by BYK-Gardner forthat tile. Nanometer numbers for 380, 540, and 720 nm must be +0.25nanometer. If the result is greater than +0.25 nm, repeat thecalibration.

Use Opacity mode: White under standard and sample. The opacitymeasurement consists of measurement of a specimen backed with a blackreference and the measurement of the same specimen backed with a whitereference. The Color measurement of the specimen can be displayed witheither the black reference or the white reference as the backing. Select“display white” for the Sample and Standard columns.

Procedure

-   -   1. Center a single specimen over the reflectance port making        sure there are no wrinkles and do not use areas with printed        ornamental designs.    -   2. Back the specimen with the black cavity.    -   3. Place the white reference (white side of black cavity) over        the specimen on the reflectance port. Do not move the specimen        test area between the black cavity reading and the white        reference reading.    -   4. Record the C2° Opacity result.

Repeat 1. to 4. for each specimen.

-   -   Report:

The opacity values in percent are reported.

All documents cited in the Detailed Description of the Invention are, inrelevant part, incorporated herein by reference; the citation of anydocument is not to be construed as an admission that it is prior artwith respect to the present invention.

While particular embodiments of the present invention have beenillustrated and described, it Would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. A disposable article selected from baby diapers,pull-on diapers, pants or adult incontinence diapers comprising a liquidpervious topsheet, a liquid impervious backsheet and an absorbent corepositioned between said topsheet and said backsheet, wherein saidbacksheet comprises at least one polymeric film and at least onenonwoven web, said polymeric film and said nonwoven web each have twomajor surfaces and said polymeric film and said nonwoven web bothcomprise a polymeric material, at least one of said polymeric materialsof said film or of said nonwoven web is colored by pigments comprisedwithin said polymeric material and wherein at least one of saidpolymeric film or said nonwoven web has visually discernible ornamentaldesigns, said designs being provided by printing a pigmented ink onto atleast one of said major surfaces of at least one of said polymeric filmor said nonwoven web and said polymeric film being joined in anoverlaying region across at least part of one of its major surfaces toat least part of an adjacent major surface of said nonwoven web to formsaid backsheet and wherein said backsheet in said overlaying region hasa L Hunter value on the Hunter scale for darkness/lightness-appearancefrom about 10 to about 75, an “a” value for red/green-appearance fromabout −50.0 to about +50.0 and an “b” value for yellow/blue-appearancefrom about −50.0 to about +50.0 in the areas outside the printedornamental designs.
 2. The disposable article according to claim 1,wherein said backsheet in said overlaying region has an opacity fromabout 55% to about 100% in the areas outside the printed ornamentaldesigns.
 3. The disposable article according to claim 1, wherein one ofsaid two major surfaces of said polymeric film and said nonwoven web isa garment facing surface and said discernible ornamental designs areprovided by printing on at least one of said garment facing surfaces ofsaid polymeric film or said nonwoven web.
 4. The disposable articleaccording to claim 1, wherein said backsheet comprises a garment facinglayer and a body facing layer and said nonwoven web is comprised by saidgarment facing layer and said polymeric film is comprised by said bodyfacing layer.
 5. The disposable article according to claim 1, whereinsaid ornamental designs comprise not more than about 50% of at least oneof the two major surfaces of said backsheet.
 6. The disposable articleaccording to claim 1, wherein more than about 60% of said ornamentaldesigns coincide with the area covered by said absorbent core.
 7. Thedisposable article according to claim 1, wherein said disposable articlecomprises a rear waist edge and said absorbent core comprises a rearcore end edge and wherein the distance between said rear end edge andsaid rear core end edge comprises at least about 40 mm.
 8. Thedisposable article according to claim 1, wherein said printing isapplied such, that the effect of an additional color is created bycovering at least a first area of at least one of said major surfaces ofat least one of said polymeric film or said nonwoven web with opaque inkin a halftoning process while covering at least a second area completelywith the same ink.
 9. The disposable article according to claim 1,wherein said printing is applied such, that the effect of an additionalcolor is created by covering at least a first area of at least one ofsaid major surfaces of at least one of said polymeric film or saidnonwoven web with a relatively thin layer of a transparent ink whileapplying a relatively thick layer of the same ink in at least a secondarea.